How do I close unwanted windows?
There is a way. You must have all margin lines aligned to be able to close your top tabs. For example, Img 1 will close, but Img 2 and Img 3 won't.

Img 1:



Img 2 &amp; 3:

 

To close your windows, collapse the top Info bar to the left by grabbing and dragging the hashmarks at the bottom-left, to the left. Then, grab the hashmarks at the top right of the bottom Info bar and drag upwards. Lastly, grab the divide line between the top of the 3D Viewport/Outliner and drag it upward to condense the Info bar.